Welterweight boxer Robert Guerrero of the U.S. is treated in his corner between rounds during his fight against Floyd Mayweather Jr., also of the U.S., at the MGM Grand Garden Arena in Las Vegas, Nevada May 4, 2013. REUTERS/Steve Marcus

Floyd Mayweather Jr. still has it together as a fighter.

A year after he last fought, Mayweather returned to the ring Saturday night at the MGM Grand Garden Arena in Las Vegas and picked up where he left off, defeating challenger Robert Guerrero in a 12-round unanimous decision to retain the WBC welterweight title.

Mayweather, considered the best pound-for-pound fighter in the world, won 117-111 on all three judges’ cards and remained unbeaten at 44-0 with 26 knockouts. The 36-year-old Mayweather was guaranteed a payday of at least $32 million for his 21st world title fight in a 17-year career.

The 30-year-old Guerrero (31-2-1 with 18 KOs) was no match for the quicker Mayweather. It was Guerrero’s first loss since 2005.

On the undercard, unbeaten Abner Mares of Mexico stopped countryman Daniel Ponce De Leon in the ninth round, scoring a technical knockout to win the WBC featherweight championship.

The victory gave Mares his third world title in three weight classes.

In the ninth round, Mares knocked down De Leon with a right hand. The challenger got up, but Mares relentlessly attacked along the ropes before referee Jay Nady stopped the bout at 2:20.

Mares (26-0-1 with 14 knockouts) was leading on all three judges’ scorecards.